The present invention relates to a trip assembly for moving a ground working implement to a tripped position when an obstruction applies a force to the implement that exceeds a preset trip load. More particularly, the present invention discloses a trip assembly that trips at predictable trip loads that are relatively insensitive to the speed at which the implement is moving.
Trip assemblies are well known and commonly utilized on plows. A known type of plow trip assembly includes two toggle members, one of which is pinned at a first point to the plow, and the other of which is pinned at a second point to a frame. The two toggle members are pinned to each other at a third point that is below a line extending through the first two points, and normally maintain the plow in a ground contacting plowing position. A force acting on the plow due to an obstruction in the ground, such as a stone, bends the third point upwardly until it crosses the line between the first and second points. When the third point crosses the line, the trip assembly trips and moves the plow to a tripped position removed from the ground.
Various types of two toggle member trip assemblies have been utilized, some of which use one relatively rigid toggle member and one relatively resilient spring toggle member. Prior art assemblies often bend the spring toggle member about a fulcrum, either between a frame and the spring toggle member, or between the spring toggle member and the rigid toggle member at a point above the center of the rigid toggle member.
Many prior art trip assemblies have problems since they may trip at forces that are below desired trip loads. In addition, most of these trip assemblies have unpredictable trip loads which are quite sensitive to the speed at which the plow is being moved through the ground. That is, the trip loads of many prior art systems vary widely as the speed of the plows varies.
Unpredictable trip assemblies may trip at trip loads that are lower than a desired trip load, resulting in undesirably frequent tripping. Each time a trip assembly trips and moves the plow to a tripped position, the operator must reset the plow to the plowing position. This is time-consuming, and thus an unpredictable, speed-sensitive plow trip assembly is undesirable.